Japan Meteorological Agency (JMA)
WMO/GAW Dobson Calibration System

    To maintain the accuracy of Dobson spectrophotometers in the WMO/GAW ozone observing network, it is important to ensure traceability through intercomparison and calibration with the world standard and the regional standard Dobson spectrophotometers. The national standard instruments are calibrated by these regional standards for each at the Regional Dobson Calibration Centres (RDCCs).
    JMA maintains and manages a reginal standard instrument for Dobson spectrophotometer in Asia (RA-II) at the Aerological Observatory in Tsukuba. This regional standard instrument is calibrated through comparison with the WMO world standard owned by NOAA once every three years. The world standard instrument itself is calibrated in Mauna Loa, Hawaii by absolute assay using the Langley method. Table 1 shows all past intercomparisons between the regional and world standards.

Table 1. Intercomparisons for Regional Standard (D116)
Year Place
1977 Boulder / USA
1984 Melbourne / Australia
1989 Maunaloa / USA
1992 Boulder / USA
1995 Arosa / Switzerland
1998 Boulder / USA
2001 Maunaloa / USA
2004 Boulder / USA
2007 Boulder / USA
2010 Maunaloa / USA
2013 Boulder / USA
2017 Melbourne / Australia

Last Updated: October 22, 2018